1. Technical Field
This invention relates to shipping pallets that are used for material handling and shipping of palletized loads in the shipping industry.
2. Description of Prior Art
Prior art shipping pallets have traditionally been made of wood planks that are nailed to spaced wood supports. The wood planks are nailed to the top and bottom surfaces of the wood supports defining a self-supporting elevated platform on which loads can be placed. The wood planks and supports are typically spaced in relation to one another and allow access for a forklift to slide under the upper planks in two access channels formed between the wood supports. While wood pallets are durable and easy to manufacture, they have a limited useful life due to the abuse during use. High quality wood pallets are repairable and reused, if possible, until they are significantly damaged and must be discarded.
Low quality or standard wood pallets are most often used for limited reshipping purposes or one-way shipping environments wherein the receiver of the palletized goods has no specific need for the pallet once received and thus becomes a disposal liability. Attempts to recycle the standard wood pallet have met with various degrees of success due to the labor involved in disassembly the damaged pallets and safety issues for workers handling wood with rusty nails, etc.
A solution to the problem associated with the disposal of wood pallets have been the introduction of the paper or cardboard pallets. Paper pallets have been made out of a variety of paper construction elements such as honeycomb, corrugated cardboard and pre-formed paper shapes such as cylinders and tubes. By use of paper pallets, allows for the total recycling of the pallet by shredding, baling and disposal as recycled paper. Paper pallets introduce a new series of problems, such as moisture, durability and load capacity versus fabrication costs. Thus the only lightweight load bearing paper pallets have been successful in the marketplace for certain load and weight requirements such as air freight or limited indoor or inter-plant shipping.
Such examples of paper pallets can be seen in U.S. Pat. Nos. 5,001,991, 5,076,176, 5,129,329, 5,195,440, 5,493,962 and 5,528,994.
In U.S. Pat. No. 5,001,991 a corrugated pallet construction can be seen having a plurality of cross support tubes engaged through stringers of tri-folded cardboard construction.
U.S. Pat. No. 5,076,176 is directed to a corrugated cardboard pallet having platform slats made of multiple layers of cardboard glued together. Transversely extending cross slots define support stringers with a plurality of spacer blocks all formed of laminated layers of corrugated cardboard.
U.S. Pat. No. 5,129,329 is a modified form of U.S. Patent ending in 176 that introduces an alternate construction wherein the top and bottom paper slats are to be formed of wood.
U.S. Pat. No. 5,195,440 discloses a paper pallet formed from sheets of foldable material. Support stringers are formed from tubular construction having tubular reinforcing vents provided within.
U.S. Pat. No. 5,493,962 claims a lightweight paper pallet having honeycomb load supporting surface structure secured to support beams made of channels of corrugated cardboard with spacer support blocks within.
A cardboard pallet can be seen in U.S. Pat. No. 5,528,994 having a sandwich and glued cardboard sheet construction and interdisposed support and spacing slots and blocks formed of laminated corrugated cardboard products.
Finally, in U.S. Pat. No. 5,601,035 a cardboard pallet is shown made of multiple layers of corrugated cardboard bonded together forming load supporting surface sheets and intersecting cross cardboard beams.